Ethylene copolymers are also referred to as polymers comprising repeat units derived from ethylene and a polar monomer such as ethylene acid copolymers by one skilled in the art and include ionomers thereof. They are useful as packaging material. These polymers are well known to one skilled in the art and, because these polymers comprise repeat units derived from polar monomers, they have properties distinct from other polymers having no repeat units derived from polar monomers such as polyethylene, polypropylene, and other polyolefins.
It is well known that the presence of fillers in a polymer resin can improve mechanical and chemical properties of the resin. While the filler may improve the tensile strength or modulus of a resin, it may decrease the resin's toughness, elongation at break or the flex modulus. By increasing the surface area to volume, such as with nanoparticles, the amount of filler needed can be reduced, thereby reducing the negative effect of the filler, while maintaining or increasing desired property improvements.
Nanoparticulates often can access properties that the bulk material cannot, such as what wavelengths that are absorbed or transmitted. For example, titanium dioxide is a well-known white pigment (generally having a size on the order of 100 nm to 1000 nm) and can absorb and scatter light in the visible region.
Nano-TiO2 particles (referring to TiO2 having particle sizes on the order of about 1 to about 100 nm) can be dispersed in water while remaining transparent in appearance. While nano-TiO2 is not absorbing or scattering light in the visible region, it absorbs in the UV region.
For example, WO2003/099911 discloses the incorporation of nano TiO2 particles in polyolefins; U.S. Pat. No. 6,667,360 discloses the incorporation of TiO2 particles in polymer resins to improve mechanical properties; and U.S. Pat. No. 6,479,576 discloses the incorporation of TiO2 particles into polyethylene or ethylene copolymers.
Many packaging applications have a need for a transparent, UV barrier film. For example, a packaging material that remains clear appeals to customers. Such packaging material can be used for foods, medicines, medical devices, and cosmetics. Such UV barrier film can increase the shelf life and reduce other measures to preserve the material packaged.
Plasticized polyvinyl butyral sheet can be used in the manufacture of laminate structures such as, for example: windshields for vehicles including automobiles, motorcycles, boats and airplanes; homes and buildings; shelving in cabinets and display cases; and other articles where structural strength is desirable in a glass sheet. In many applications, it is desirable that the laminate shields undesirable UV light and/or be transparent. Additionally a variety of decorative glass laminates can be useful in a variety of applications; use of decorative glass laminates is not widespread in end-use applications such as furniture, cabinetry, countertops, tabletops, and the like.
Therefore, there is a continuing need for improving polymer properties, without sacrificing the current properties, for packaging, bottles, laminated glass, especially transparent ethylene copolymer films that exhibit a barrier to the transmission of ultra-violet light.